Stitch presser for knitting machine

ABSTRACT

A stitch presser for a knitting machine equipped with at least two needle beds arranged in an inverted &#34;V&#34;, and provided with needles which intersect during their upward movement, a carriage movable above the needle beds, a system for control of the needles during their displacement in alternate directions, and a means for the alternate control of the stitch presser along a row of needles and in another adequate position for the movement in the opposite direction wherein the stitch presser acts between two needle beds on the stitches held by the needles. The stitch presser includes a slide thread for pressing the knitwear and a supplementary means for pressing the stitches against the needle beds.

BACKGROUND OF THE INVENTION

The present invention relates to a stitch presser for knitting machines.More particularly, the present invention provides a stitch presser witha slide presser for pressing the knitwear and a supplementary means forpressing the stitches against the needle beds.

In a flat knitting machine where the needles are controlled in bothoscillating movements of the carriage by lock fixed below said carriageit is known to mount a device for the control of the stitch presserdirectly on the carriage, so that one of the slide threads constitutingthe pressing member of the stitch presser operates when the carriage ismoved in an opposite direction. It is also customary to assign onestitch presser device to each knitting system or to each pair ofknitting systems, if the knitting is done on two needle beds.Furthermore, it is known to assign one stitch presser to each knittingsystem or to each pair of knitting systems when the knitting is done ontwo needle beds and to modify the position of the stitch presser at theend of each stroke of the carriage, so that it is possible tosuccessively work in two opposite directions.

Stitch pressers traditionally include slide threads of different shapesand are sometimes completed by other means such as rollers, bladescrapers or brushes, all being afflicted with the disadvantage of beinguseable for only part of the knitting fabrics and particularly not formixed fabrics, for example, one form of slide thread can be used onlyfor a limited lock or mesh density and a selected fabric. The stitchpressers equipped with rollers, blade scrapers, brushes, etc., presentthe inconvenience of discontinuity of action on the knitwear i.e., thespace between the roller scraper, or brush, and the beginning of a slidethread is not controlled.

SUMMARY

The stitch presser of the invention includes a slide thread and asupplementary means whose field of action is at least partiallysuperposed over the field of action of the slide thread and whose fieldof action starts ahead of the first point of crossing of the needles,seen in the moving direction of the carriage. Normally the field ofaction of the supplementary means will also end ahead of the end of thecomplete upward movement of the needles. The cumulative width of thefield of action will ordinarily be at least equal to the spacingmeasured between two needle beds. The slide thread presses the knitwearand the supplementary means acts to press the stitches against theneedle beds to improve on the conventional action of the slide threadwhich often results in irregular columns of stitches on the knitwear dueto excessive friction between the slide thread and the stitch.

Preferrably, the supplementary means is a fluid, for example, compressedair or water, or an auxiliary slide including additional slide threads.

It is advantageous to mount a valve at the fluid distribution point, inorder to direct it toward one or another principal slide threaddepending on whether the carriage is moved in one direction or in theopposite direction. It is also advantageous for the fluid to be directedin a direction which is not perpendicular to the movement of thecarriage.

Accordingly, the primary object of the invention is to provide a simpledevice which is easily adaptable to a stitch presser, which controls thefriction between the slide thread and the knitwear. Another object is areturn means for a stitch presser, acting in the space between the twoneedle beds, independently of the thickness of the yarn or the kind ofknitwear.

The novel features which are believed to be characteristic of theinvention are set forth in the appended claims. The invention itself,however, together with further objects and attendant advantages thereof,will be best understood by reference to the following description takenin connection with the accompanying drawings, in which:

FIG. 1 is a partial view of a stitch presser for a knitting machineaccording to the invention:

FIG. 2 is a front view of a stitch presser according to the invention;

FIG. 3 is a partial section along 3--3 of FIG. 2;

FIG. 4 is a schematic representation of the fields of action of oneslide thread and of the compressed air jets in relation to the needlebeds and the trajectories of the needles;

FIG. 5 is a section of the needle beds at a larger scale, just ahead ofthe point of intersection of the needles;

FIG. 6 is similar to FIG. 5 for a different knitwear material;

FIG. 7 is a front view of a variation according to the invention;

FIG. 8 is a view along 8 of FIG. 7;

FIG. 9 is a representation similar to FIG. 4;

FIG. 10 shows a section of the needle beds on a larger scale and of theslide threads along 10 of FIG. 7; and

FIG. 11 is a section similar to FIG. 10, along 11 of FIG. 7 for anotherknitwear fabric.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The stitch presser 1 represented in FIG. 1 comprises two stitch pressingmeans 2. Each stitch pressing means 2 consists of a slide thread 3 whichoperates when the knitting carriage is moved from right to left on theknitting machine, and of a slide thread 4 which works when the carriageis moved in the opposite direction.

The stops 5 and 6 are used to reverse the stitch pressers after thecarriage has arrived at its end of stroke.

The fixation means of the stitch pressing device on the carriage and thereversing means of the stitch pressers are known from prior art andoutside the scope of this invention. They are neither described norshown.

The slide threads 3 and 4 form one piece with a support 7 which in turnis mounted by means known and not shown, on the lever 8.

A pipe for supplying compressed air forms one piece with the support 9.It includes two pipes 11 and 12 respectively to conduct compressed airtoward the slide threads 3 and 5 respectively.

The pipes 11 and 12, shown in FIG. 3, include a baffle 13, therebyseparating the end of the pipes into two nozzles 14 and 15. The supplyof compressed air is accomplished via the flexible pipe 16 connected onthe one hand to the pipe 10 and on the other hand to a device which mayor may not form one piece with a knitting machine, and capable ofsupplying said compressed air. This kind of device is known, it isoutside the scope of the invention and thus not shown. Provisions aremade to mount, at the point of distribution 17, a valve making itpossible to direct compressed air toward pipe 11 or pipe 12, dependingon whether the carriage is moved from the right to the left or from theleft to the right, on the knitting machine.

The fields of action 18 and 19 of the nozzles 14 and 15 respectively areshown schematically in FIG. 4. The slide thread 3 will have a field ofaction 20 shown between the two fields of action of the nozzles.

Reference symbols 21 and 22 show the start and end, respectively of thefield of action of the slide thread 3.

Reference symbols 23 and 24 show the start and end, respectively of thefields of action 18, 19 of the nozzles 14, 15.

The start of the field of action (23) of a nozzle is located ahead ofthe first crossing point 25 of the needles viewed in the direction ofmovement of the carriage, and ends ahead of the end of the completeupward movement of the needles in stitch formation. The curves 26 and 27respectively, drawn in dots and dashes represent the trajectories of theneedle hooks working on a front needle bed 28, and/or of a rear needlebed 29 of a knitting machine.

The fields of action 18, 19 of the nozzles are superposed over the fieldof action of the slide thread 3, so that they commence after the start21 and terminate prior to the end 22 of the field of action 22 of theslide thread 3.

The cumulative width of the fields of action is at least equal to thedistance between the two needle beds 28, 29.

During the knitting on two needle beds 28, 29, the knitwear 30 is heldby the stitches 31 in the needle hook 33 and by the stitches 32 in theneedle hook 34.

The arrangement shown is the one we find just prior to the needles beingmoved by the locks of the knitting carriage.

The slide thread 3 presses on the knitwear 30 and the compressed airspouts 35 and 36 originating from the nozzles 14 and 15 respectivelypress the stitches 37 and 38 against the needle beds 29 and 28respectively. During the start of the upward movement of the needles,the stitches 31, 32 expand and the slide thread 3 along with thecompressed air jets 35, 36, press the knitwear 30 downward, so as tomake sure that the stitches 31, 32 remain taut. During the upwardmovement the compressed air spouts 35, 36 aid the stitch 31, 32, toslide along the needle body 33a, 34a.

The combination of the two elements, compressed air and slide thread,make possible the judicious dimensioning of the slide thread, to avoidexcessive friction of the slide thread on the stitch, which could causeirregular columns of stitches to appear on the knitwear, that is columnswhich would not be strictly straight, with the knitting on one needlebed 29 only, the same device may be used. FIG. 6 is a view similar toFIG. 5, but for knitting on one needle bed only. In that case, theaction of the slide thread 3 on the knitwear 39 is considerably reduced,it has a tendency to slide on the knitwear to be placed in the freespace remaining between said knitwear 39 and the opposite needle bed 28.On the other hand, the compressed air spout 35 remains completely activeand suffices to compensate for the lack of work furnished by the slidethread 3.

Thus it is readily understood that such an apparatus allows for theknitting on one and two needle beds in one and the same row of stitchesor in different rows of stitches.

It may be advantageous to direct the fluid in a direction which is notperpendicular in relation to the movement of the carriage, so as tocontribute toward a possible balancing of the stitches.

The stitch presser shown in FIGS. 7 and 8 is a variation of theadditional device mentioned in the object of our invention.

It consists of the principal slide threads 40, 41 and auxiliary flexibleslide threads 42, 43, 44, 45. The principal slide threads 40, 41 formone piece, by way of fixation means 46, with a support 47 which ismounted to the lever 8 by means known and not shown.

The auxiliary flexible slide threads 43, 45 are placed in grooves 48, 49located in slot 50. By their shapes they are positioned directly. Theauxiliary flexible slide threads 42, 44 are placed in an identicalmanner in a crosspiece 51, all of this being fixed with the aid of acover 52 and fixation means 53. A compression spring 54 is located onthe one hand in the housing 55 of the slot 50 and on the other handagainst the support 47.

The auxiliary flexible slide threads 42, 43 and 44, 45, are provided sothat they can be concealed on each side of the principal slide thread40, 41 respectively.

The fields of action of the above mentioned slide threads, in spacing ofthe needle beds are shown in FIG. 9.

The reference symbols 56 and 57 show the start and the end respectivelyof the field of action 58 of a principal slide thread 41.

The reference symbols 59 and 60 represent the start and end respectivelyof the fields of action 61 and 62 of the auxiliary flexible slidethreads 45 and 44. The end 60 of the fields of action 61, 62 of saidflexible auxiliary slide threads is located, seen in the direction ofmovement of the carriage, after the start 56 and prior to the end 57 ofthe field of action 58 of a principal slide thread 41. The fields ofaction 61, 62, 58 thus are partly superposed.

The curve 63 and 64, represent the trajectory of the needle hooksworking on a front (28) and a rear (29) needlebed of a knitting machine.

The cumulative width of the fields of action 61, 58, 62, is at leastequal to the distance separating both needle beds 28, 29.

The fields of action 61, 62 of the auxiliary flexible thread slidescommence, seen in the operating direction of the knitting carriage,prior to the first crossing point 65 of the needles, and terminate priorto the complete upward movement of the needles.

During the knitting on two needle beds 28, 29 (FIG. 10), the stitches 31and 32 are maintained in the hook 33 and 34, of the needles. The needleshave not yet moved upward. The principal slide thread 41 presses on theknitwear 30. The auxiliary flexible slide threads 45 and 44 pressagainst the needle beds 29 and 28 and on the already formed stitches 37and 38. To arrive in this position, the auxiliary flexible slide threads45, 44 have been compressing the compression spring 54 by the movementthey have caused to the slot 50. The end of the auxiliary flexible slidethreads 44, 45 is found just below the roof (or inverted V-shaped part)formed by the crossing of the needles. To facilitate the comprehensionof the drawing, the following needles which have already started theirupward movement or which have partly moved upward, are not shown.

During the knitting on one needle bed 29 only, according to FIG. 11, theauxiliary flexible slide thread 45 presses the knitwear 39 downward andagainst the needle bed 29, the auxiliary flexible slide thread 44, likethe principal slide thread 41, are used as self-centering elements ofthe slide threads in the spacing of the needle beds. The slot 50 (FIG.7) is in low position, under this action of the compression spring 54.

It thus is readily understood that with such a device it is possible toknit fabrics on one or two needle beds and even mixed fabrics in one andthe same knitting row.

A mixed contexture of fabric will cause a back and forth movement of theslot 50, enabling it to assume the position according to FIG. 10 oraccording to FIG. 11, depending on whether the auxiliary flexible slidethreads 44, 45 are located in one knitting range on two needle beds(FIG. 10) or on one needle bed (FIG. 11).

The knitter thus has in his hands a simple apparatus, enabling him toconsiderably increase the field of application of the stitch pressers.He has a self-adjustable system as to width which no longer is afunction of the contexture of the knitwear. He has thus a device workingin the entire area separating the needle beds and particularly very nearthe needle beds.

Of course, it should be understood that various changes andmodifications in the preferred embodiments described herein will beapparent to those skilled in the art, such changes and modifications canbe made without departing from the spirit and scope of the presentinvention and without diminishing its attendant advantages. It is,therefore, intended that such changes and modifications be covered bythe following claims.

What is claimed is:
 1. An improved stitch presser for a knitting machineequipped with the following:at least two needle beds arranged in aninverted V-shape; needles capable of intersecting during their upwardmovement; a carriage movable above the needle beds; a system for controlof the needles during their displacement in alternate directions; astitch presser which acts between the two needle beds on the stitchesheld by the needles; and means for alternate control of the stitchpresser in a position adequate for the movement of said stitch presseralong a row of needles and in another position adequate for the movementin the opposite direction; wherein the stitch presser comprises a slidethread for pressing the knitwear and a supplementary means for pressingthe stitches against the needle beds, the field of action of thesupplementary means being at least partially superimposed over the fieldof action of the slide thread and whose field of action starts ahead ofthe first point of crossing of the needles, seen in the moving directionof the carriage.
 2. The stitch presser of claim 1 wherein the field ofaction of the supplementary means ends ahead of the end of the completeupward movement of the needles, and wherein the cumulative width of thefield of action of said slide thread and said supplementary means is atleast equal to the spacing measured between the needle bed.
 3. Thestitch presser of claim 1 wherein the supplementary means is a nozzlethrough which a fluid is ejected to press the stitches against theneedle beds.
 4. The stitch presser of claim 3 wherein the nozzle ejectsthe fluid in a direction which is not perpendicular to the movement ofthe carriage.
 5. The stitch presser of claim 4 wherein the fluid iscompressed air.
 6. The stitch presser of claim 5 wherein the fluid is aliquid.
 7. The stitch presser of claim 2 wherein the supplementary meanscomprises a flexible thread slide mounted on a slot working against theeffect of a compressible member.
 8. The stitch presser of claim 7wherein the compressible member is a spring.
 9. An improved stitchpresser for a knitting machine equipped with at least two needle bedsarranged in an inverted V-shape, with needles capable of intersectingduring their upward movement, with a carriage movable above the needlebeds, with a system for control of the needles during their displacementin alternate directions, and with a stitch presser which acts betweenthe two needle beds on the stitches held by the needles and whichincludes means for alternate control of the stitch presser in a positionadequate for the movement of said stitch presser along a row of needlesand another position for the movement in the opposite direction;whereinthe stitch presser comprises a slide thread and supplementary meanswhose field of action is at least partially superposed over the field ofaction of the slide thread and whose field of action starts ahead of thefirst point of crossing of the needles, seen in the moving direction ofthe carriage.
 10. The stitch presser of claim 9 wherein the field ofaction of the supplementary means ends ahead of the end of the completeupward movement of the needles, and wherein the cumulative width of thefield of action of said slide thread and said supplementary means is atleast equal to the spacing measured between the needle bed.